Half-width circuit breaker modification for full width load centers



Nov. 1, 1966 G. w. KNECHT ETAL 3,233,110

HALF-WIDTH CIRCUIT BREAKER MODIFICATION FOR FULL WIDTH LOAD CENTERSFiled Oct. 21, 1964 INVENTORS ALEXANDER A. NORDEN GEORGE w. KNECHTATTORNEY United States Patent York Filed Oct. 21, 1964, Ser. No. 405,35315 Claims. (Cl. 200-168) This invention relates to circuit breakers andpanels or load centerstherefor, and in particular to an arrangement forelectrically and mechanically connecting a circuit breaker of a givenwidth to a load center constructed to receive circuit breakers ofgreater width.

The conventional load center, for home and light industrial application,comprises two or more power buses from which bus-blades project in aparallel array; the blades of the buses being alternated so thatneighboring blades are associated with opposite polarity buses. Thespacing between adjacent blades is approximately one inch and isdesigned to accommodate the standard oneinch Width circuit breaker.

Several years ago half inch width circuit breakers made their appearanceon the market, and while panelboards may be constructed specifically toutilize what will be hereinafter referred to as half-width breakers, itis highly desirable to utilize existing panelboards adapted for thestandard width breakers. In addition, it is often economically desirableto construct a single panelboard which will have the flexibilityutilizing both the standard and half-width circuit breakerssubstantially interchangeably.

The conventional circuit breaker, be it single or double pole, isdesigned with a receptive contact clip centered at the lower frontcorner. When applied to a bus-blade, the breaker sits astride the bladewith the contact clip gripping its opposite sides and one half of thebreaker width overhanging the blade on either side. Since a neighboringunit is likewise disposed on a bus-blade one-inch away, the two unitsare contiguous. At this point it bears mentioning that further spaceoptimization is achieved by making the bus-blade length sufiicient toengage two clip-on units in front end abutment. Thus, it may be said asa general proposition that conventionally the number of clip-on unitpairs in a row equals the number of bus-blades.

The innovation of half width breakers would at first appear to doublethe circuit breaker capacity of a given load center. However, it isapparent, that the reduced width is not significant in this regard ifthe conventional clip-on feature is retained, since the maximum numberof units per blade remains at two.

Accordingly, it is an object of this invention to provide a circuitbreaker-load center arrangement which optimizes the use of includedspace.

It is another object of this invention to provide means for adaptingnarrow circuit breakers, particularly half inch width breakers, topanelboards designed to receive larger width circuit breakers,particularly one-inch width breakers.

It is a further object of this invention to provide a circuit breakerportion which is operatively juxtaposed to the bus-blade with a bladecontact (i.e. one whose function it is to contact the bus-blade) capableof being disposed on either the left or right of the breaker, dependingupon the side of the bus-blade on which the circuit breaker is located.

It is a further object of this invention to provide means for properlyseating a half-width circuit breaker unit in a standard panelboard;means for imparting contact pressure to the circuit breaker bladecontact; and means for directing the circuit breaker blade contact tothe proper side of the breaker.

It is a further object of this invention to satisfy the last mentionedobject with a single adapter.

It is a further object of the invention to provide by coaction of thebreaker housing and adapter, the spacing and insulation required betweenconductors of differing polarity.

It is a still further object of this invention to defeat the use of theinventive breaker without the aforementioned adapter.

Briefly, the invention is predicated upon the concept of providing acircuit breaker with an internal chamber communicating with a pair ofwindows disposed on the other side of the breaker at the portion thereofoperatively positioned between bus-blades; a flexible blade con tactmounted within said chamber with a portion centrally located between thewindows; and adapter means mechanically coupling the bus-blade andcircuit breaker for seating the latter with respect to the former andpiloting the flexible blade contact contiguous the adjacent bus-blade.

The above mentioned and other features and objects of this invention andthe manner of attaining them will become more apparent and the inventionitself will best be understood by reference to the following descriptionof an embodiment of the invention taken in conjunction with theaccompanying drawings wherein:

FIG. 1 is an exploded perspective view of the front end of a circuitbreaker and the associated adapter according to the invention;

FIG. 2 illustrates one-half of the circuit breaker module shown in FIG.'1;

FIGS. 3 and 3a illustrate the blade contact, its disposition in thecircuit breaker, and its degree of movement;

FIG. 4 shows an attempt to incorrectly mount the circuit breaker; and

FIG. 5 illustrates an array of bus-blades with conventional andhalf-width circuit breakers mounted thereon.

Refren'ng now to the figures and in particular to FIGS. 1 through 3a,the novel circuit breaker and adapter will now be described. Circuitbreaker module or unit 10 is composed of two mating housing sections 12and 14, preferably molded of an insulator material and joined togetherby any suitable means such as the rivets 16. The cooperating sections 12and 14 form a cavity 18 (FIG. 2) within which the blade contact will bedisposed. Communicating with the cavity 18, at the lower front end ofthe circuit breaker is a centrally located slot 20 providing an accessmeans and a pair of laterally offset windows 22 and 22.

At this juncture, it bears mentioning that the circuit breaker front endwill be defined herein as that portion of the breaker to be operativelypositioned in juxtaposed relationship to the bus-blade of the loadcenter; and window will be defined herein as that portion of the breakerthrough which the breaker contact exits for operative contact with abus-blade.

Disposed within the chamber 18, and electrically and mechanicallycoupled, for example by welding, to the electromagnet coil 24 (FIG. 3)of the pole mechanism is the blade contact 30. This contact is composedof a flexible conductive material such as spring bronze, and comprisesan upper leaf portion 32 and an integral nose portion 34; the latter ofwhich is'provided (for a reason that will become apparent) an internalresiliency by virtue of the told 34. The extreme lower portion of thenose section is formed to preclude penetration into this section frombelow by the bus blade. This may be conveniently accomplished byserrating or side lapping the abutting edges.

To ensure suflicient resiliency and return of the blade,

contact to its symmetrical location within the cavity when 3non-operational, it is depended at the leaf section 32 by the 1clamp 28(FIG. 3a). The clamp itself may be simply formed of abutting portions ofthe mating housing sections, one of which 28' is shown in FIG. 2 at thetop of the chamber 18.

FIG. 1 also illustrates the adapter or blade clip 40, so called becauseit adapts the breaker module to a left or right positioning with respectto the bus-blade and also ridesor clips the blade; thereby positioningthe front end of the breaker while simultaneously compensating for theside-wiping force of the blade contact which in the absence of thestabilizing force imparted by the adapter in conjunction with thebus-blade would effect a lateral breaker movement.

The adapter is composed of high impact insulator material such as moldedpolycarbonate resin and comprises a frontal plate member 41, containinga slot 42.communicating with the bottom and adapted to sit astride abus-blade. A pair of wings 44 and 46 are disposed on either side of theplate, extending to the rear thereof. The wings are dimensioned toenterthe circuit breaker slot and are adapted by the upper cammingsurfaces 44' and 46' to pilot the blade contact to the right and left,respectively. This may be done by inserting the adapter into the breakerby hand or by inserting the breaker over the adapter when the adapterhas already been positioned on the blade as in the case when it isalready in use holding another breaker in place. Each wing has a taperedlip (for example 46") on the outer edge thereof for cooperating with theouter frame of the corresponding window (forexample 23, FIG. 2) to guidethe blade tight against the front face of the circuit breaker; thelatter, being with a similar window frame portion in breaker section 14.

Assuming now the circuit breaker is to be mounted to the left of abusblade (such as shown in FIG. 5, breaker D) the leftwing 44 would beinserted into the slot 20, its upper surface 44' thereby camming thebreaker contact to the right into the window 22, in side-wiping relationto the bus-blade 53; simultaneously providing a wall of insulationbetween the breaker contact of breaker D and the opposite polaritycontact of breaker C. The slot 42 of the adapter will now appearapproximately even with the right face of the circuit breaker and isinserted over a bus-blade to position the front end of the breaker. andsimultaneously compensate for the side-wiping force produced by theadapter wing 44 against the blade contact.

Insertion of the other wing 46 into the circuit breaker slot 20 will ofcourse produce a mirror image eflie'ct (equivalent to breaker C in FIG.5). Thus it may be seen that regardless of which side it is used on, theblade clip cooperates with the bus-blade and blade contact to become amember-in-tension maintaining contact pressure between bus-blade andblade contact.

FIG. 4' illustratesa feature of the invention for defeating an attemptto erroneously seat the circuit breaker on a bus-blade 50. Sufiice tosay, that since the blade contact is centrally locatedwithin the breakercavity (in the absence of the use of the blade clip) the nose portion ofthe blade contact 30 will abut the top of the bus-blade, therebypreventing the seating of the front end of the breaker, and thereforethe closing of the load center cover (not shown).

FIG. 5 illustrates an array of bus-blades, with the halfwidth circuitbreakers of the invention mounted thereon in several distinctcombinations. The circuit breaker designated by the letter A is astandard clip-on breaker and is shown in this figure so that theinventive arrangement may be contrasted therewith and so that it willbe' clearly appreciated that both the standard and inventivearrangements may coexist in a single load center. For the purposes ofillustration, it may be assumed that blades Pole Adapter 1. Single poleleft X 2. Single pole right Y 3. Duplex X, 4. 2-pole opposite polarityX-Y Apparent from the foregoing is the .fact that a single adapter maybe associated with two circuit breakers to establish the conventionalduplex arrangement.

For the sake of clarity and to avoid detracting from the invention, onlythe front ends of the circuit breakers have been shown and described.For a description of the rear portions, and their cooperation with theload center reference may be had to copending application Serial No.233,738, filed October 29, 1962, now Patent No. 2,198,992 to a commonassignee. Further, it will be appreciated that wihile specific widthdimensions have been set forth to provide an environment for theinvention, these may be varied and are ultimately dependent only uponthe load center bus-blade configuration.

While we have described above the principles of our invention inconnection with specific apparatus, it is to be clearly understood thatthis description is made only by way of example and not as a limitationto the scope of our invention as set forth in the objects thereof and inthe accompanying claims. For example, the inventive concept may easilybe adapted to the entire breaker of the above denoted copendingapplication by merely adding the front end slot described herein andnormally positioning the blade contact so that it lies internally of thebreaker sides in a non-'bus-blade contacting attitude. The adaptermember wings may then, upon insertion in the slot, cam or key thebreaker contact outwardly into its operative position.

We claim:

1. A circuit breaker adapted to be disposed on either side of a loadcenter bus-blade for electrical contact therewith comprising:

.a housing having an internal chamber communicating with the exteriorthrough a .pair of windows disposed on either side of the breaker at thefront end thereof;

a flexible blade contact mounted within said chamber for movement of aportion thereof tosaid windows, said contact having a nose portioncentrally located between said windows; a

said housing including external access means for allowing maneuvering ofsaid first mentioned portion of said flexible blade contact.

2. The circuit breaker claimed in claim 1 in combination with means forguiding the nose portion of the contact to either of said windows andmaintaining said breaker front end contiguous a bus-blade.

3. A circuit breaker adapted to be disposed on either side of a loadcenter bus-blade for electrical contact therewith comprising:

a housing [having an internal chamber communicating with the exteriorthrough a pair of windows disposed on either side of the breaker at thefront end thereof and with a slot located at the underside: of the frontend between said windows and extending centrally up a portion of thefront end face; and

a flexible blade contact mounted within said chamber for movement of aportion thereof to said windows,

said contact having a nose portion centrally located between saidwindows.

4. The circuit breaker claimed in claim 3 in which 'said housing iscomposed .of two mating sections, and

said flexible blade contact is mounted within said chamber by abuttingportions of said sections acting as a clamp upon a portion of saidcontact.

5. The circuit breaker claimed in claim 3 in which said contact is asingle relatively flat metal stamping, a section of which is folded overto form said nose portion.

6. The circuit breaker claimed in claim 3 in combination with means forguiding the nose portion of the contact to either of said windows andmaintaining said breaker front end contiguous a bus-blade.

7. The combination claimed in claim 6 in which said guiding meanscomprises a front plate having an elongated slot therein for embracing abus-blade, and a pair of wings disposed on either side of said plateparallel to said elongated slot and extending to the rear of said plate,each of said Wings for entering the housing slot and urging the bladecontact nose portion to the window intermediate the wings.

8. The combination claimed in claim 7, in which the front platedimension perpendicular to the included slot approximately equal thewidth of the circuit breaker.

9. The combination claimed in claim 7 in which each of said wingscontains a camming surface at the upper end thereof for initiallycontacting the nose portion of the contact blade.

10. The combination claimed in claim 7, in which each of said wings hasa laterally offset tapered portion, said housing having a pair ofcorresponding surfaces said chamber, each for engaging a wing at thetapered portion to guide the adapter member front plate snug to thefront end of the circuit breaker.

11. The combination claimed in claim 10 in which the front end of thecircuit breaker housing is recessed to flush mount the front plate.

12. An adapter member for circuit breaker bus-blade keying comprising afront plate having an elongated slot therein communicating with one endof said plate, and a pair of wings laterally ofiset on either side ofsaid slot and extending to the rear of said plate.

4 13. The combination of a circuit breaker adapted to be mounted oneither side of a load center bus-blade for electrical contact therewithcomprising:

a housing having an internal chamber communicating with the exteriorthrough a pair of Windows disposed on either side of the breaker at thefront end thereof and with .a slot located at the underside of the frontend and extending up a portion of the front face,

a flexible blade contact mounted within said chamber and normallydisposed internally of the side planes of said breaker;

and an adapter member having an elongated slot therein for embracing abus-blade and including means entering said breaker slot and keying saidflexible blade contact outwardly of said breaker and contiguous the saidbus-blade,

whereby in the absence of said adapter member said breaker contactremains in a non-bus-blade contacting position.

14. The combination claimed in claim 13, in which said adapter membercomprises a front plate having an elongated slot therein for embracing abus-blade, and a pair of breaker-slot-entering wings disposed on eitherside of said plate parallel said elongated slot and extending to therear of said plate.

'15. The combination of: a circuit breaker adapted to be disposed oneither side of a load center bus-blade, said breaker having a contactmember normally spaced from the adjacent bus-blade when inserted in saidload center; and an integral adapter member comprising means forcarnming said breaker contact member against said busblade and means forrigidly positioning said circuit breaker in said load center.

References Cited by the Examiner UNITED STATES PATENTS 3,095,524 6/1963Leonard et a1. 317-119 X ROBERT K. SCHAEFER, Primary Examiner.

KATHLEEN H. CLAFFY, Examiner.

H. O. JONES, Assistant Examiner.

1. A CIRCUIT BREAKER ADAPTED TO BE DISPOSED ON EITHER SIDE OF A LOADCENTER BUS-BLADE FOR ELECTRICAL CONTACT THEREWITH COMPRISING: A HOUSINGHAVING AN INTERNAL CHAMBER COMMUNICATING WITH THE EXTERIOR THROUGH APAIR OF WINDOWS DISPOSED ON EITHER SIDE OF THE BREAKER AT THE FRONT ENDTHEREOF; A FLEXIBLE BLADE CONTACT MOUNTED WITHIN SAID CHAMBER FORMOVEMENT OF A PORTION THEREOF TO SAID WINDOWS, SAID CONTACT HAVING ANOSE PORTION CENTRALLY LOCATED BETWEEN SAID WINDOWS; SAID HOUSINGINCLUDING EXTERNAL ACCESS MEANS FOR ALLOWING MANEUVERING OF SAID FIRSTMENTIONED PORTION OF SAID FLEXIBLE BLADE CONTACT.